Study: HDL Cholesterol (or ‘Good’ Cholesterol) May Not Be That Good for You
The term “cholesterol” is thrown around a lot to describe a waxy substance that can build up in your arteries, but there are actually two forms of cholesterol—LDL and HDL. LDL cholesterol is known as “bad” cholesterol, while HDL cholesterol is generally considered “good” cholesterol. But a new study has found that HDL cholesterol isn’t as protective against heart disease as experts previously though—especially for Black adults.
That’s the takeaway from research funded by the National Institutes of Health (NIH) that was published in the Journal of the American College of Cardiology. For the study, researchers analyzed data from 30,239 people enrolled in the Reasons for Geographic and Racial Differences in Stroke (REGARDS) cohort. The study participants were 45 and older, and data was collected over about 10 years.
After analyzing the data, the researchers determined that high levels of LDL cholesterol and triglycerides (components of fat and oils) were linked with an increased heart disease risk in both Black and white adults. But the researchers also found that, while low levels of HDL cholesterol were linked with a higher risk of heart attack in white adults, the same wasn’t true for Black study participants.
Also worth noting: Higher levels of HDL cholesterol didn’t reduce the risk of heart disease for either group.
The idea that HDL cholesterol is good for you stems from a study conducted in the 1970s that determined high levels of HDL were linked with a low heart disease risk, explains Alfonso Waller, M.D., a cardiologist and associate professor at Rutgers New Jersey Medical School. “But it primarily looked at a white cohort,” he says. “There have been other studies that, when they were looking at white cohorts, reinforced that. But whenever it’s been studied in multi-ethnic groups, it hasn’t panned out as being cardio-protective.”
OK, so what does this mean for HDL cholesterol and how concerned should you be about yours? Here’s the deal.
What is cholesterol?
Cholesterol is a waxy substance that your body needs to build cells, and make vitamins and other hormones, according to the American Heart Association (AHA). However, too much cholesterol can be body for your body.
There are two main sources of cholesterol, per the AHA:
Your liver. This organ actually makes all of the cholesterol your body needs.
Animal products. Meat, poultry, and dairy products contain cholesterol. They also are high in saturated and trans fats, which cause your liver to make more cholesterol than it otherwise would.
Why can cholesterol be bad?
Cholesterol circulates in your blood and having too much cholesterol raises your risk of cardiovascular diseases like heart disease and stroke, the AHA explains. It’s generally thought that too much LDL cholesterol and not enough HDL cholesterol increases the risk that cholesterol will build up in the inner walls of the arteries that go to your heart and brain.
When that build-up happens, it can narrow your arteries and make them less flexible (a condition called atherosclerosis), the AHA explains. And, if a blood clot forms and blocks a narrowed artery, it can lead to a heart attack or stroke.
Is HDL cholesterol bad, too?
Not necessarily. “HDL cholesterol has historically been referred to as the ‘good’ cholesterol because HDL particles pick up cholesterol around the body and bring it back to the liver to be processed,” says Yu-Ming Ni, M.D., a cardiologist at MemorialCare Heart and Vascular Institute at Orange Coast Medical Center in Fountain Valley, Calif. “Think of HDL particles as the clean-up crew, whose job is to clean up after the LDL particles.”
But Dr. Ni says that there is a “sweet spot” for HDL cholesterol that reduces the risk of bad heart events. “Too little, and there isn’t enough clean-up going on,’ he says. “Too much might mean the cleaning crew is overwhelmed and unable to do their job of preventing heart disease.”
The study doesn’t necessarily say that Black adults don’t benefit from HDL, Dr. Ni says. Instead, it suggests that they “do not have a clear sweet spot for HDL cholesterol.”
But, he adds, “this suggests that other factors may have a greater influence on cardiovascular health, particularly in the presence of other medical conditions such as high blood pressure, diabetes, and obesity.” Dr. Ni says that the study is “useful” for understanding cardiovascular risk in different patients, but stresses that “treating the whole picture is often more beneficial.”
Thomas F. Boyden, M.D., medical director of Cardiovascular Rehabilitation and Metabolic Wellness at Spectrum Health Medical Group, points out that while the study “highlights a potential key difference in populations,” it “does not identify the cause of this difference.” As a result, he says, more studies are needed to try to figure out what’s going on here.
How to lower your cholesterol levels
It’s tempting to read this and think you should be working to lower your HDL cholesterol levels, too, but Dr. Boyden says that’s not the case. Instead, he says, “our efforts at treating cholesterol focus predominately on lowering the bad cholesterol and improving the ratio between the good and bad cholesterols.” Meaning, you really want to try to keep your LDL cholesterol levels low, regardless of who you are.
There are a few things you can do to lower your LDL cholesterol, per the AHA, including:
Eat a heart-healthy diet, focusing on fruits, vegetables, whole grains, poultry, fish, and nuts, while limiting red and processed meats, sodium, and sugary foods and drinks.
Strive to do at least 150 minutes of moderate-intensity aerobic exercise a week.
Avoid smoking.
Try to maintain a healthy weight.
Overall, Dr. Waller says, “the big takeaway is that we should be focusing on other factors for high cholesterol, including social determinants of health or uncontrolled risk factors like hypertension, smoking, and physical activity.”
Dr. Boyden agrees. “This study does not change the current clinical approach of targeting LDL-cholesterol for minimizing coronary heart disease risk,” he says.
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